Interface Superconductivity

Abstract

This chapter focuses on aspects that are related to the nature of superconducting fluctuations and the fact that in generic interfaces the three-dimensional inversion symmetry is broken. The realization and characterization of interface superconductivity, i.e. of two-dimensional superconducting phases in various different systems, constitute a topic of significant current interest. Superconductivity is most-widely studied in bulk systems. Some of the most widely investigated and interesting systems, such as the cuprates, organic charge transfer salts, and some of the iron-based materials are structurally and electronically highly anisotropic. A well-established aspect of two-dimensional superconductivity is the distinct nature of superconducting fluctuations. The Hohenberg theorem implies that a two-dimensional superconductor will not give rise to a finite expectation value of the order parameter. The most dramatic phenomenon in two-dimensional superconductivity is, however, the fact that they have, despite the absence of a finite order parameter expectation value, a finite superfluid stiffness.